Providing configurable workflow capabilities

ABSTRACT

Techniques are described for providing clients with access to functionality for creating, configuring and executing defined workflows that manipulate source data in defined manners, such as under the control of a configurable workflow service that is available to multiple remote clients over one or more public networks. A defined workflow for a client may, for example, include multiple interconnected workflow components that are specified by the client and that each are configured to perform one or more types of data manipulation operations on a specified type of input data. The configurable workflow service may further execute the defined workflow at one or more times and in one or more manners, such as in some situations by provisioning multiple computing nodes provided by the configurable workflow service to each implement at least one of the workflow components for the defined workflow.

BACKGROUND

As the amount of data that is generated and used by software programs has grown, the complexity of managing and analyzing such data has also increased in at least some situations. In addition, as software programs increasingly execute in online and other networked environments, the data to manage and analyze is increasingly accessible in disparate locations and manners, which may increase the complexity of managing and analyzing such data. Thus, various problems exist in managing and analyzing data that is generated and used by software programs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example embodiment of a configurable workflow service that provides functionality to enable remote clients to create, configure and execute defined workflows that manipulate source data in defined manners.

FIGS. 2A-2B illustrate examples of using a defined workflow to manipulate source data in particular manners in particular situations.

FIG. 3 is a block diagram illustrating an example embodiment of a computing system configured to provide a configurable workflow service that manages use of defined workflows for supported client systems.

FIG. 4 illustrates an example embodiment of a flow diagram for a Configurable Workflow Service routine.

FIG. 5 illustrates an example embodiment of a flow diagram for a Workflow Component Worker Process routine.

DETAILED DESCRIPTION

Techniques are described for providing clients with access to functionality for creating, configuring and executing defined workflows that manipulate source data in defined manners, such as under the control of a configurable workflow service that is available to multiple remote clients. In at least some embodiments, a remote client may interact with a configurable workflow service over one or more public networks in order to create and configure a defined workflow that is provided by the configurable workflow service for use by the client—such a defined workflow may, for example, include multiple interconnected workflow components that each are configured to perform one or more specified types of data manipulation operations on a specified type of input data. After a client has configured such a defined workflow, the configurable workflow service may further execute the defined workflow at one or more times and in one or more manners, such as in some situations by provisioning multiple computing nodes provided by the configurable workflow service to each implement at least one of the workflow components for the defined workflow, and by retrieving defined types of source data and providing it to workflow components in defined manners. Thus, in at least some embodiments, some or all of the described techniques are automatically performed by embodiments of a configurable workflow service, such as may be implemented by one or more software modules executing on one or more configured computing systems, as described in greater detail below.

As noted above, a defined workflow may include multiple workflow components, which may be of multiple types in at least some embodiments, including to have one or more data source workflow components that correspond to input data for the defined workflow, one or more data manipulation workflow components that correspond to defined data transformations or other manipulations to be performed on data, and one or more data destination workflow components that correspond to providing output data from the defined workflow. In addition, interconnections may be defined between workflow components that correspond to data flows between workflow components, such that data output from a first component may be supplied as input to a second component, with that relationship being represented as a connection from the first component to the second component. In at least some embodiments and situations, the configurable workflow service may provide a group of predefined workflow components that a client may select and use in a defined workflow of the client, optionally after being configured in one or more manners. Furthermore, in at least some embodiments and situations, the configurable workflow service may enable a client to supply or otherwise define some or all workflow components to be used in a defined workflow of the client.

Each data source workflow component that is defined for a workflow may correspond to obtaining data from an indicated data source, and may include information such as a storage location for the data, and optionally additional access information related to the storage location (e.g., login information associated with the client; a particular search or other information to use to identify data to be used, such as related to metadata and/or data contents; etc.). In some embodiments, the configurable workflow service may provide internal storage locations for use by clients in storing their source data, with a particular data source corresponding to such an internal storage location, while in other embodiments and situations, a particular data source may be external to the configurable workflow service, such as one or more network-accessible storage systems that are provided by or otherwise controlled by the client, one or more online storage services, one or more online data generation services, etc. A non-exclusive list of examples of online storage services that may be used include the following: Amazon Simple Storage Service (S3) that stores object data of various types; Amazon Relational Database Service (RDS) that provides relational database functionality; Amazon SimpleDB that provides functionality to store key-value pairs; Amazon DynamoDB service that provides NoSQL database functionality; Amazon Elastic Block Store (EBS) that provides access to raw block storage devices, including to enable mounting a virtual local block storage device on a target computer system; etc. A non-exclusive list of examples of online data generation services includes an RSS feed, the Amazon Cloudwatch Service that provides monitoring functionality for executing applications and services and generates corresponding information, etc. Data sources may thus be of various forms, such as a relational or other database (e.g., the HBase open-source distributed database, the BigTable distributed database, the MongoDB database system, the Apache Cassandra distributed database management system, etc.), a hash table, a file system, an object store, etc., optionally implemented in a distributed manner, and a non-exclusive list of examples of data groups that may be obtained from a data source includes a file (e.g., a Web server log), a database row or other record, a stored data object, a streamed group of data, etc.

Thus, in some situations and embodiments, a particular defined workflow may obtain and use data from multiple data sources, with some or all of the data sources optionally being external to the configurable workflow service. In addition, the configurable workflow service may optionally predefine one or more types of data source workflow components, such as to correspond to a particular internal storage mechanism of the configurable workflow service, to correspond to one or more particular online storage services (e.g., online storage services that are integrated with or otherwise affiliated with the configurable workflow service, or that instead are unaffiliated with the configurable workflow service), etc. Similarly, a client may optionally define one or more data source workflow components, such as to correspond to a client-specific storage location, to an online storage service without a predefined data source workflow component, etc.

Each data manipulation workflow component that is defined for a workflow may correspond to performing one or more defined data transformations or other manipulations on data that is input to the data manipulation workflow component. In addition, the output from a data manipulation workflow component may be provided to a data destination workflow component to be provided to a client, or instead may be intermediate data that is provided to a next data manipulation workflow component, such as via one or more electronic messages, by storing the intermediate data in a storage location accessible to the next data manipulation workflow component (e.g., using one or more storage locations provided by the configurable workflow service), etc. Defined data manipulations may be of various forms, including to perform a defined type of calculation on one or more groups of input data, to aggregate multiple groups of input data in one or more manners, to select a subset of one or more groups of input data, to move data from one storage location to another, etc. A non-exclusive list of example data manipulations includes performing a distributed data copy, performing one or more SQL (Structured Query Language) transforms, performing one or more map and/or reduce functions within a map-reduce architecture (e.g., for use within the Amazon Elastic MapReduce service), using a scientific or mathematics package (e.g., MatLab, Mathematica, etc.), executing a client-supplied script or other program, etc. Thus, in some situations and embodiments, a particular defined workflow may perform multiple data manipulation operations via multiple defined data manipulation workflow components, using predefined and/or client-defined data manipulation workflow components.

Each data destination workflow component that is defined for a workflow may correspond to providing output data from the defined workflow to one or more storage locations and/or in one or more manners. The types of storage locations used by data destination workflow components (and corresponding information stored for such data destination workflow components) may be similar to or the same as for data source workflow components in at least some embodiments, including to use storage locations that are internal to and/or external from the configurable workflow service. In addition, in at least some embodiments and situations, particular data destination workflow components may include preparing and providing output data in particular manners, such as to generate particular types of reports, to send output data via one or more types of defined electronic communications, etc. Thus, in some situations and embodiments, a particular defined workflow may provide multiple types of output data in multiple manners via multiple defined data destination workflow components, using predefined and/or client-defined data destination workflow components.

In addition, a client may define a workflow in various manners in various embodiments. For example, an embodiment of a configurable workflow service may provide one or more interfaces for use by a client, such as a defined GUI (“graphical user interface”), a defined API (“application programming interface”), and/or a defined CLI (“command line interface”). When using a provided GUI, a user representative of a client may, for example, use a visual editor to specify particular workflow components for a workflow being defined, and may further specify interconnections between particular workflow components corresponding to data flows—in at least some such embodiments, the configurable workflow service may represent the defined workflow as a graph that logically represents the workflow, with various graph nodes corresponding to particular workflow components. FIG. 2A provides additional illustrative details with respect to an example of such a workflow graph.

The configurable workflow service may further implement a defined workflow for a client in various manners and at various times. In some embodiments, each time that a defined workflow is to be used, the configurable workflow service instantiates a physical copy of the logical graph representing the defined workflow, such as by using multiple computing nodes that each implement at least one workflow component for the defined workflow. In particular, in at least some embodiments, some or all of the computing nodes are provisioned by the configurable workflow service to configure those computing nodes to implement particular workflow components (e.g., to load corresponding software and/or data on those computing nodes), such as to each execute a workload worker process corresponding to each such implemented workflow component. The computing nodes may have various forms in at least some embodiments, including to each be a separate physical computer system, a separate virtual machine (e.g., one of multiple virtual machines hosted on a physical computer system), a group of multiple physical computer systems that are operating in a distributed manner, etc. Some or all such computing nodes used for a defined workflow may in some embodiments be selected from a plurality of computing nodes provided by the configurable workflow service for use by clients. In addition, some or all such computing nodes may be provided by or otherwise controlled by the client and/or may be provided by one or more online execution services, whether instead of or in addition to computing nodes provided by the configurable workflow service. A non-exclusive list of example online execution services that may be used include the Amazon Elastic Compute Cloud (“EC2”) program execution service, the Amazon Elastic MapReduce service for performing distributed map-reduce operations (e.g., by using a cluster of computing systems from the service to represent or implement a computing node for the configurable workflow service), etc. In addition, when a particular defined workflow is to be implemented multiple times, the configurable workflow service may in some embodiments maintain the provisioning and availability of some or all computing nodes for the defined workflow between two or more such times of implementing the defined workflow (e.g., in accordance with instructions from the client, based on an automated determination by the configurable workflow service, etc.), while in other embodiments may release some or all such computing nodes to be available after an implementation and provide the same types of provisioning of computing nodes (optionally different computing nodes) for a next implementation.

A defined workflow may further have additional types of associated information in at least some embodiments and situations. For example, a client may specify information that indicates when to implement a defined workflow, such as based on a client instruction for immediate implementation, by scheduling future implementation at one or more defined future times, by scheduling one or more future implementations when one or more defined criteria are satisfied (e.g., based at least in part on availability of particular source data), etc. Defined criteria may be specified in various manners, such as to be associated with particular workflow components or instead with the defined workflow as a whole. For example, a particular workflow component may have defined precondition criteria to evaluate to determine when to execute the workflow component, and/or may have defined post condition criteria to evaluate when to complete execution and/or provide data that is produced (e.g., to a next workflow component, to an intermediate storage location, etc.). In some embodiments and situations, a defined workflow may further have one or more associated alarms that may be used to provide notification to a client (or to perform other activities) when one or more specified criteria are satisfied or are not satisfied (e.g., if a defined workflow is not implemented at a particular time, such as if particular source data is not available).

The configurable workflow service may further be a fee-based service in at least some embodiments, such that clients of the configurable workflow service are customers that pay fees to the configurable workflow service for at least some of the functionality provided by the configurable workflow service. In addition, when one or more online storage services and/or online execution services are used by the configurable workflow service as part of implementing a particular defined workflow for a particular client, such other services may also optionally charge fees for such use, whether via the configurable workflow service or directly to the client.

Thus, use of the configurable workflow service may provide various benefits in various embodiments and situations, including to enable a client to schedule gathering data from multiple sources at particular times or otherwise when particular criteria are satisfied, to perform defined types of data manipulation operations on the source data, and to provide output data produced by the defined workflow in various manners. Additional benefits are discussed elsewhere herein, and will otherwise be appreciated by those skilled in the art.

For illustrative purposes, some embodiments are described below in which specific instances of defining and implement workflows are provided in specific ways, including with respect to specific types of data, specific types of data manipulation operations, and specific types of storage services and execution services. These examples are provided for illustrative purposes and are simplified for the sake of brevity, and the inventive techniques can be used in a wide variety of other situations, some of which are discussed below, and the techniques are not limited to use with particular types of data, storage or other devices, computing systems or computing system arrangements.

FIG. 1 is a network diagram that illustrates an example embodiment of a configurable workflow service 110 that manages creation and execution of defined workflows for various clients of the configurable workflow service. As part of implementing a defined workflow, the configurable workflow service 110 further provisions particular computing nodes to each perform specified activities corresponding to the defined workflow. In some embodiments, the configurable workflow service 110 optionally provides a group of computing nodes 140 on which defined workflows for clients may be executed. In other embodiments, some or all of the computing nodes used by the configurable workflow service may be provided externally to the configurable workflow service, such as by a client on whose behalf the defined workflow is implemented, by one or more online execution services, etc. In addition, in some embodiments, the configurable workflow service 110 optionally includes one or more storage nodes 150 on which data may be stored to facilitate the execution of defined workflows. For example, the storage nodes 150, if present, may be used to store intermediate data results that are produced during execution of a defined workflow, and in some embodiments may further be used to store source data that is provided to a defined workflow and/or final output data produced by a defined workflow. While not illustrated in FIG. 1, the configurable workflow service may be implemented using one or more configured computing systems, as described in greater detail with respect to FIG. 3 and elsewhere.

FIG. 1 further illustrates one or more networks 190, and various client computing systems 160 via which clients of the configurable workflow service 110 may interact with the service 110 to define and execute workflows. The network(s) 190 of FIG. 1 may include any appropriate network or combination of networks, including an intranet, the Internet, one or more private networks with access to and/or from the Internet, a cellular network, a local area network, or any other such network or combination thereof. Communications over the networks may be enabled by wired or wireless connections and combinations thereof.

In some embodiments, the configurable workflow service 110 may provide one or both of a GUI (not shown) and/or an API (not shown), such as to enable clients to perform various interactions with the service 110. For example, a user representative (not shown) of a particular client may locally interact with one of the client computing systems 160 to cause further interactions to occur with the configurable workflow service 110 over the network 190. The user may, for example, interact with a workflow editor module 120 of the configurable workflow service, via which the user may define one or more workflows of interest for the client. As part of the interactions with the user, the configurable workflow service 110 may store various client information 112 regarding the client and optionally the user representative, and may store a particular definition of a newly defined workflow for the client as part of information 114. In some embodiments, the defining of a particular workflow may include actions by the user in selecting one or more defined workflow components and specifying the interactions between those workflow components, such as by using one or more predefined system-provided workflow component definitions 116—in other embodiments, the configurable workflow service 110 may not provide any such system-provided predefined workflow components. As part of defining a new workflow, the user may further specify one or more source locations at which source data is to be retrieved and used for the workflow definition, and one or more destination locations to which data that is produced by the defined workflow will be provided. The various information 112, 114, and 116 used by the configurable workflow service 110 may further be stored on one or more systems that support or provide the configurable workflow service 110, such as a database of the configurable workflow service, although such systems are not illustrated with respect to FIG. 1.

In addition, the user representative of the client may optionally in some embodiments define one or more new workflow components as part of defining a new workflow, and if so, such client-defined workflow components may further have definition information stored in information 116 in at least some embodiments. While a client-defined workflow and any client-defined workflow components may in some embodiments be treated as private unless otherwise specified by the client (e.g., to be accessible or otherwise visible only to that client unless other specified), in other embodiments and situations, at least some such client-specific information may instead be made available to other clients in specified circumstances, such as to enable other clients to use some or all of the client's defined workflow components and/or workflows (e.g., for a fee or for other benefits provided to the client who defined such information, if the client who defined such information approves use by others, etc.). In a similar manner, source data used by a client's defined workflow and final output data produced by a client's defined workflow may in at least some embodiments be treated as private to that client unless otherwise specified, although in other embodiments some or all such source data and/or final output data may instead be made available to other clients in specified circumstances (e.g., for a fee or for other benefit to the client with which that data is associated, if the client associated with such information approves use by others, etc.).

When a client indicates one or more storage locations from which source data may be obtained and/or to which final output data may be provided for a defined workflow, such storage locations may have various forms in various embodiments, as discussed in greater detail elsewhere. As one example, in at least some embodiments, the configurable workflow service may be integrated with or otherwise affiliated with one or more particular optional online storage services 145, such as to form a single system 105 (e.g., a single system that is operated by a single entity). If so, interactions 147 with such optional online storage services 145 may be performed to retrieve source data and/or to store final output data. Furthermore, in at least some embodiment, intermediate data results that are generated during execution of a workflow may similarly be stored in such online storage services 145, such as to be produced by a first part of the defined workflow and to be later accessed and used by a second defined part of the workflow, whether in addition to or instead of one or more optional storage nodes 150. Moreover, in at least some embodiments and situations, one or more online storage services 170 are available over the network 190 to the client computing system 160 and to the configurable workflow service 110, and may be used in a similar manner over the network(s) 190, whether in addition to or instead of some or all of the optional online storage services 145. In addition, in at least some embodiments and situations, a particular client may provide one or more client-specific storage systems or other storage locations using one or more other computing systems 185, which may similarly be used over the network(s) 190.

After a client has interacted with the configurable workflow service to define a workflow, the client may further interact with a workflow engine module 130 of the configurable workflow service to initiate execution of the defined workflow. The execution of a particular workflow may be initiated in various manners, such as to be performed immediately upon a corresponding instruction from the client, to occur at a specified future time or when other specified criteria (such as for one or more defined preconditions) are satisfied that will initiate execution of the workflow, etc. As with the workflow editor module 120, the workflow engine module 130 may in some embodiments provide a GUI interface and/or and API interface for use by clients. When the execution of a defined workflow is initiated, the workflow engine module 130 in the example embodiment retrieves workflow definition information for that defined workflow from the information 114, and initiates the execution of the defined workflow on one or more computing nodes. In particular, the workflow definition may be constructed with various logical nodes that each correspond to defined operations and are interconnected in various manners, and the workflow engine module 130 may select particular computing nodes to use to perform particular such operations, as well as to further perform activities to provision and initiate execution of corresponding workflow worker processes on each such selected computing node. As part of provisioning such computing nodes and/or of executing workflow worker processes on the computing nodes, additional interactions with one or more storage locations may be performed to obtain input data to be used and/or to store results data that are produced, including for intermediate results data for use by other workflow worker processes of the defined workflow.

Some or all of the computing nodes used to implement a defined workflow may, for example, be selected from optional computing nodes 140 provided by the configurable workflow service 110, if present, and workflow worker processes 142 may be executed on those computing nodes to implement the defined operations. In other embodiments, the workflow engine module 130 may use computing nodes that are not provided by the configurable workflow surface 110, whether instead of or in addition to the optional computing nodes 140. For example, in some embodiments and situations, a particular client may provide or otherwise control one or more other computing systems 185, and the workflow engine 130 may configure and use such other computing systems 185 as computing nodes for use in executing that client's defined workflow. In addition, in some embodiments, one or more online program execution services 148 and/or 175 may be available for use in executing programs in various manners, and if so may be used to provide computing nodes (not shown) to execute some or all of a particular client's defined workflow—for example, the workflow engine module 130 may provision and initiate execution of particular workflow worker processes on particular computing nodes provided by such online program execution services. As one example, in at least some embodiments, the configurable workflow service may be integrated with or otherwise affiliated with one or more particular optional online program execution services 148 (whether in addition to or instead of one or more optional storage services 145), such as part of a single system 105 as described above. If so, interactions 149 with such optional online program execution services 148 may be performed to provision computing nodes, initiate execution of particular workflow components, receive output data produced by particular workflow components, etc.

In other embodiments, the configurable workflow service 110 may perform additional techniques, such as to generate and provide particular types of source data for defined workflows, to perform additional activities with respect to managing final output data produced by clients' defined workflows, etc. In addition, the configurable workflow service 110 may be implemented in some embodiments based on software instructions that execute on one or more server computing systems to program or otherwise configure the server computing system(s) to perform some or all of the described techniques, such as to program one or more hardware CPU processors (not shown) of the server computing system(s)—such software instructions may, for example, be used to implement the modules 120 and/or 130, or instead the functionality of the configurable workflow service may be provided using other types of modules.

In this manner, the configurable workflow service 110 provides various benefits to various external clients, including to enable the clients to define workflows that may be executed using computing and storage resources of the configurable workflow service 110 in part or in whole, to interact with various types of online data sources to obtain data to be manipulated, and to provide output data that is produced for storage or other use. Additional details related to particular operations of the configurable workflow service 110 are included elsewhere herein.

Although the foregoing example embodiment of FIG. 1 is described with respect to a configurable workflow service 110 that provides various types of functionality in conjunction with one or more client systems that each may have one or more associated users, it will be appreciated that various other embodiments may exist. For example, in at least some embodiments and situations, a client may represent an organization or other group (e.g., a company that has multiple people instead of an individual person). Thus, a client entity may have various forms in various embodiments.

In some embodiments, the configurable workflow service 110 and optionally any online storage services and/or online program execution services that are used may each operate according to one or more fee-based structures or agreements. For example, access to some or all of the described techniques from the configurable workflow service 110 may in some embodiments be provided in a fee-based or other paid manner to a provider or operator of the configurable workflow service 110 and/or to at least some client systems that use described techniques of the configurable workflow service 110. As one example, clients of the configurable workflow service 110 may pay one-time fees, periodic (e.g., monthly) fees, and/or one or more types of usage-based fees to use functionality provided by the configurable workflow service 110. Such fees may be based on one or more factors and activities, such as indicated in the following non-exclusive list: based on a quantity and/or type of interactions performed to define a particular workflow; a size and/or type of a defined workflow and/or of some or all of its defined workflow components; based on usage of a defined workflow, such as a measure of computing resources used in executing a defined workflow (e.g., a quantity of computing nodes used), a measure of processor capability used (e.g., CPU cycles), an amount of time that occurs during the execution of the defined workflow, activities in provisioning computing nodes for a defined workflow, amount of time during which computing nodes that are provisioned for a defined workflow are unavailable for other use, such as while those computing nodes wait for source data to be available or other preconditions to be satisfied, based on a quantity of data that is stored and/or transferred, such as based on a size of the data, an amount of time of the storage, etc.; based on content or other characteristics of particular data groups that are stored, manipulated and/or produced; etc.

FIGS. 2A-2B illustrate examples of defining and executing a workflow for a client in particular manners in particular situations. In particular, in the examples of FIGS. 2A-2B, a client has access to Weblog data (such as from a Web site operated by the client, or instead in other manners), and desires to analyze that data to determine information of interest. In particular, in this example, the client desires to perform periodic (e.g., every three hours) analysis of the Weblog data in order to identify clickstream data of particular users of the Web site, and to aggregate that clickstream data in one or more manners (e.g., to determine aggregate information for particular defined age groups of the users of the Web sites). After the clickstream data is aggregated in the defined manners, it may further be used in various manners, including to be stored in a database of the client for later use, as well as to be used to generate one or more reports that are provided to the client via one or more electronic communications.

In particular, with respect to FIG. 2A, a particular client of the configurable workflow service (referred to in this example as “Customer C”) has defined a new workflow that includes various nodes and interconnections, such as based on various interactions with a workflow editor module of the configurable workflow service, or instead by performing one or more programmatic interactions with a defined API of the configurable workflow service to provide information about the defined workflow in a defined manner (e.g., by uploading a file or otherwise specifying one or more data structures to represent the defined workflow). In this example, the defined workflow is represented with a logical graph 200 that includes various nodes.

In FIG. 2A, the Customer C has defined two data source nodes 220 to represent two types of sources of data for the defined workflow. The first data source 220 a corresponds to the Weblog data that becomes available periodically, which in this example is stored by an online storage service 205. In particular, in this example the online storage service 205 stores various data groups 206 and 207 (e.g., files), and the node 220 a that corresponds to the Weblog data source includes information to use to select one or more particular data groups 207 from the online storage service that represent the Weblog data for the client. The node 220 a may include various criteria to use to identify particular data groups 207, such as a file name or other metadata associated with a particular data group, one or more specified criteria with respect to content of the data groups 207 (e.g., a time frame corresponding to Weblog data to be used to extract records from a database that correspond to a time period of interest), etc. The node 220 a may further include various access information to be used to obtain the data groups 207 from the online storage service 205, such as account information or other access information for Customer C at the online storage service with which the data groups 207 are associated. In addition, in this example the Customer C has defined one or more preconditions as part of node 225 a that are associated with the data source node 220 a, such as to indicate that the execution of node 220 a and then the rest of the workflow is to begin when the data groups 207 that satisfy the specified criteria for the node 220 a are available. In other embodiments, the preconditions 225 a or other configuration information for the execution of the defined workflow may have other forms, such as to indicate that the workflow is to be executed at a particular time, or after a particular amount of time has passed since the last execution of the defined workflow. Thus, the preconditions 225 a may, for example, be implemented in a worker process that interacts with the online storage service 205 to determine when the data groups 207 are available, and then initiates execution of a worker process corresponding to node 220 a—in at least some embodiments, the configurable workflow service may wait to implement some or all nodes of the workflow 200 other than a precondition node 225 a until those preconditions are satisfied, such as to provision a computing node to execute the worker process corresponding to node 220 a after the preconditions have been satisfied.

In addition to the Weblog data source node 220 a, the Customer C has also defined a data source node 220 b that corresponds to a database of the client, such as may be stored on one or more storage systems (not shown) under control of the client or instead that are available via an online database storage service (not shown). In this example, the database 210 of the Customer C includes various data groups 211 and 212 (e.g., database records), with the data groups 212 storing clickstream data that has been previously generated for the Web site of the client, whether by previous executions of this or a similar workflow, or instead in other manners. In this example, the node 220 b does not include any defined preconditions, such as based on the database data being known to be present, or instead based on the database data being optional for the execution of the defined workflow (e.g., so that the current Weblog data will be added to and aggregated with any previously stored clickstream data, but will generate new clickstream data to be stored even if such existing clickstream data does not exist).

In addition to the data source nodes 220, the Customer C has further defined various data manipulation nodes 235 a-280 a that are part of the defined workflow. The defined nodes 235 a-280 a of the workflow each specify one or more data manipulation operations to be performed on specified source data, and to perform particular activities with the results of those defined data manipulation operations. In particular, in this example the Customer C has defined a first node 235 a that is interconnected with the data source node 220 a, with the node 235 a being configured to perform data manipulation operations that involve extracting clickstream data for various users from the Weblog data that is provided by the data source node 220 a. As discussed in greater detail elsewhere, the data manipulation operations may be specified in various manners, including with particular program code to be executed, database operations to be performed (e.g., specified in SQL or in another defined database manipulation format), via use of defined mathematical or scientific libraries or functions, etc. Furthermore, particular data manipulation operations may be specified in other manners in other embodiments, such as to combine some or all of the defined nodes 235 a-280 a in a fewer number of nodes (e.g., one), and/or to separate the data transformation operations of node 235 a into multiple distinct nodes.

In this example, after the data manipulation node 235 a performs its data manipulation operations, the intermediate results of those data manipulation operations are configured to be provided to a next data manipulation node 240 a, which in this example is configured to associate each group of clickstream data that is extracted by node 235 a with a particular user. For example, the clickstream data provided by node 235 a may be grouped and associated with a unique identifier for each user, but may lack further identifying information about the corresponding users. The data manipulation operations of node 240 a may include identifying particular users, and determining corresponding information for those users. For example, an age of each user may be obtained and used in node 240 a to be associated with the user's corresponding clickstream data that was extracted in block 235 a. Accordingly, the intermediate results output data from block 240 a includes a group of clickstream data corresponding to particular users that are identified by age, and are configured in this example embodiment to be provided a next data manipulation node 245 a that is defined for the workflow. While not illustrated in this example, the data manipulation node 240 a may further in some embodiments obtain user-related data from another data source node (not shown) to enable its operations, such as from one of the illustrated source locations 205 or 210, or instead from a different source location (not shown).

The data manipulation node 245 a is defined in this example embodiment to aggregate the various clickstream data and associated users from node 240 a by defined groups of ages, such as to aggregate clickstream data for users in age groups 18-25, 26-50, 51-65, and 66+. Thus, the intermediate results from the data manipulation operations of node 245 a may include summary information for one or more clickstream measures for each defined age group, such as number of pages viewed, amount of time spent per page or per site, particular types of activities performed, etc. These intermediate data results produced by the node 245 a are configured in the illustrated example to be provided to a data manipulation node 275 a that combines this new clickstream data with other preexisting clickstream data if available.

In addition, while the nodes of the defined workflow are illustrated in the example of FIG. 2A in a logical manner that shows interconnections between the nodes in an abstract manner, in some embodiments, the defined workflow may further include additional details about how the implementation of the defined workflow is to occur during execution. For example, some or all of the nodes of the defined workflow may include details about particular storage locations from which to obtain the data that the node is to use, and/or particular storage locations in which the results of the node are to be stored. Thus, with respect to data manipulation node 245 a, the node may further be defined to optionally store the intermediate data results that it produces in a particular specified storage location, which is illustrated in FIG. 2A as optional intermediate storage 250. Such intermediate storage 250 may, for example, correspond to one or more of optional storage nodes 150 of FIG. 1, optional online storage services 145 of FIG. 1, online storage services 170 of FIG. 1, etc. As one specific example, the intermediate storage 250 may be the online storage service 205, and the node 245 a may be configured to store its results as one or more particular data groups 208 (not shown) on the online storage service, such as by specifying a particular data group name or other storage location of the online storage service in which the intermediate results from node 245 a will be stored. In a similar manner, if such an intermediate storage location is specified for node 245 a, the next node 275 a in the node graph may include a defined input storage location that is that same storage location from which to obtain those intermediate data results produced by the node 245 a. Additional details of the user of such intermediate storage locations are described in further detail with respect to the example of FIG. 2B. In other embodiments, the configurable workflow service may manage the transfer of data between workflow components, whether by using one or more intermediate storage locations that are automatically selected by the configurable workflow service, by performing message passing, etc.

In addition, as previously noted, the Customer C has in this example previously generated data groups 212 on the database 210 that correspond to previously existing clickstream data for the client. Such clickstream data may, for example, include some or all of the types of clickstream data that is aggregated with respect to node 245 a, and may further include various other types of clickstream data that does not correspond to node 245 a, such as with respect to other data groups 211 of the database 210. In addition, the data source node 220 b was previously defined to extract those data groups 212 that correspond to the clickstream data of interest for this defined workflow. Accordingly, the Customer C further defines a data manipulation node 270 a that is configured to receive those data groups 212 from the clickstream data source node 220 b, and to retrieve particular clickstream data of interest corresponding to the defined age groups and types of clickstream data of node 245 a. The data manipulation operations of node 270 a may include, for example, extracting particular data records from the database 210, or may include additional types of operations (e.g., performing one or more database join operations to combine data from multiple database tables of the database, performing one or more database select operations to select a subset of data from a database table, etc.). Thus, the intermediate data results provided by the data manipulation of node 270 a include the same types of clickstream data and the same types of defined age groups as were previously noted with respect to node 245 a. In other embodiments, one or more of the nodes 235 a-245 a may instead manipulate the new clickstream data to match the database record structure of the data groups 212.

Thus, the data manipulation node 275 a is configured to receive intermediate data results that are produced by node 245 a, and is further configured to receive intermediate data results produced by node 270 a. When both types of data are available, the node 275 a is configured to combine the clickstream data of the defined types by the defined age groups. The intermediate data results produced by the node 275 a are then configured to be used in two distinct manners in this example. In particular, the Customer C has further defined two data destination nodes 230 that correspond to two defined destinations to which the data produced by the defined workflow will be provided. In particular, a first data destination node 230 a is defined to correspond to the database 210 of the Customer C, and in particular to correspond to the same set of data groups 212 as does the data source node 220 b. Thus, when the intermediate data results of node 275 a are produced and made available to the data destination node 230 a, those data results are configured to be sent to the database 210 as final output of the defined workflow, and to be stored as part of the data groups 212, such as by adding additional data records to the database to supplement the previously existing data that was retrieved by node 220 b, or to instead replace some or all of the previously retrieved data with new updated data that further includes the information from the most recent set of Weblog data.

In addition to storing the updated clickstream data in the database 210, the Customer C further defines a data destination node 230 b that corresponds to communicating a generated report to the Customer C via one or more electronic communications sent to a mailbox 290 of the Customer C. Thus, the defined workflow 200 further includes a data manipulation node 280 a that is defined to take the intermediate results from the node 275 a and to perform data manipulation operations that include generating a report in a defined manner that includes some or all of the clickstream data from node 275 a (e.g., optionally just the new clickstream data output by node 245 a). The intermediate data results generated by the node 280 a, which in this example are configured to include one or more defined reports that present information in a structured manner, are provided to the data destination node 230 b, which is configured to provide that final output of the defined workflow 200 to the mailbox 290 of the Customer C via one or more electronic communications.

Thus, in the illustrated example of FIG. 2A, the Customer C client of the configurable workflow service has defined a workflow 200 that, when implemented, combines data of different types from different sources to produce multiple types of output data of interest to the client, which is automatically made available to the client in multiple specified manners.

FIG. 2B continues the example of FIG. 2A, and in particular provides additional details related to an example implementation of the defined workflow 200 of FIG. 2A. In particular, FIG. 2B illustrates various computing nodes 140 that have been configured to perform various workflow worker processes 225 b-280 b that correspond to the logical nodes 225 a-238 a of the defined workflow graph 200.

As discussed in greater detail elsewhere, the computing nodes 140 may come from one or more sources, including by using one or more computing nodes provided by the configurable workflow service, by using one or more computing nodes made available by the Customer C client, and/or by using one or more computing nodes provided by each of one or more external online execution services. When accessing computing nodes made available by the Customer C client, the configurable workflow service may optionally use access information supplied by the Customer C client to enable interactions with those computing nodes (e.g., to provision the computing nodes, to execute software on the computing nodes, etc.). When accessing computing nodes from an external online execution service for use on behalf of the client, the configurable workflow service may in some embodiments and situations use information for the client as part of interactions with the online execution service, such as information for an existing account of the client with the online execution service—if so, the computing nodes from the online execution service that are being used by the configurable workflow service may in at least some such situations also be accessible to the client via interactions between the client and the configurable workflow service. Alternatively, when accessing computing nodes from an external online execution service for use on behalf of the client, the configurable workflow service may in some embodiments and situations use an account of the configurable workflow service with the online execution service, such that the online execution service considers those computing nodes to be associated with the configurable workflow service rather than the client—if so, those computing nodes from the online execution service that are being used by the configurable workflow service on behalf of the client may in at least some such situations not be accessible (or possibly even visible) to the client, including based on any interactions between the client and the configurable workflow service.

FIG. 2B includes the online storage service 205 of FIG. 2A, although it does not illustrate details about the particular data groups 206 and 207 that are stored by the online storage service 205. In this example, the configurable workflow service has selected and provisioned a first computing node E 140 e to perform a workflow worker process 225 b that corresponds to the preconditions node 225 a of the defined workflow 200, such as by determining whether the defined preconditions are satisfied (e.g., by performing one or more interactions 257 to determine whether particular source data from the online storage service 205 that corresponds to the data groups 207 of FIG. 2A are available). When the preconditions are satisfied, the workflow worker process 225 b initiates the performance of a next worker process 235 b, such as by providing corresponding instructions (not shown) to the configurable workflow service. The configurable workflow service has further selected and provisioned a computing node A 140 a to perform the workflow worker process 235 b in this example, which corresponds to the node 235 a of the defined workflow 200. In particular, the worker process 235 b of FIG. 2B performs one or more interactions 255 a to obtain source data from the online storage service 205 that correspond to the data groups 207 of FIG. 2A, such as by using information defined with respect to the source node 220 a of FIG. 2A, and in accordance with the preconditions for the node 225 a of the defined workflow 200 being satisfied.

The worker processes 225 b and 235 b may in some embodiments and situations execute at different times, on different types of computing nodes (e.g., if the computing node E is provided by the configurable workflow service, and the computing node A is provided externally to the configurable workflow service), in different manners (e.g., with worker process 225 b executing on a single physical computing system that provides computing node E, and with worker process 235 b executing in a distributed manner on multiple physical computing systems that provide computing node A), etc. Thus, while a particular worker process such as worker process 235 b is illustrated as a single process in the example of FIG. 2B, it will be appreciated that actual worker processes may be implemented in various manners in various embodiments, including by using one or more physical computing systems to represent the computing node that executes the worker process, whether provided by the configurable workflow service or instead by one or more online program execution services that are external to the configurable workflow service.

In the illustrated example, after the worker process 235 b receives the source data via interactions 255 a and performs the data manipulation operations described with respect to node 235 a of FIG. 2A, the worker process 235 b generates intermediate data results that are stored in online storage service 205 via one or more interactions 225 b with the online storage service. While the particular intermediate results are not illustrated in the example of FIG. 2B, the results may be stored in various manners, as described with respect to the intermediate storage 250 of FIG. 2A, including in a particular storage location that is configured as part of the node 235 a and/or the worker process 235 b.

After the intermediate results have been stored via the interactions 225 b, a worker process 240 b executing on computing node B 140 b performs more interactions 255 c with the online storage service 205 to obtain those intermediate data results for use, optionally based on the use of one or more preconditions (not shown) that are satisfied when those intermediate data results are available. In particular, in this example the configurable workflow service has selected computing node B to execute worker processes 240 b and 245 b that correspond to the nodes 240 a and 245 a of FIG. 2A, respectively. Thus, with respect to the worker process 240 b, the process performs one or more data manipulation operations previously described with respect to node 240 a of the FIG. 2A. In this example, because the computing node B is executing multiple worker processes, the intermediate data results produced by the worker process 240 b are not stored in the online storage service 205, but are instead passed directly via interactions 255 d to the worker 245 b, such as via in-memory access or instead via one or more other types of electronic communications. In other embodiments, the worker process 240 b may instead store such intermediate data results with the online storage service even if the next worker process 245 b in the dataflow will later retrieve and use those same intermediate data results.

In this example, the executing worker process 245 b next performs the data manipulation operations previously described with respect to node 245 a of FIG. 2A, including to use the intermediate data results produced by the worker process 240 b and to generate its own intermediate data results, which in this example are stored in the online storage service 205 via one or more interactions 255 e. While the online storage service 205 is used to store the intermediate data results of multiple distinct worker processes in this example, in other embodiments the intermediate data results of the various worker processes may be stored in other manners, including to store intermediate data results of different worker processes in different online storage services, or instead in other manners.

In addition to the online storage service 205 of FIG. 2A, FIG. 2B also illustrates the database 210 of the Customer C client, although the example data groups 211 and 212 of FIG. 2A are not illustrated in FIG. 2B. In this example, the configurable workflow service has further selected a computing node C 140 c to execute a worker process 270 b that corresponds to the node 270 a of the workflow 200 of FIG. 2A. Thus, the worker process 270 b of FIG. 2B performs one or more data manipulation operations previously described with respect to node 270 a, including to perform interactions 255 f with the database 210 to obtain the data groups 212 defined with respect to the data source node 220 b. In this example, the worker process 270 b similarly stores its intermediate data results in the online storage service 205 via one or more interactions 255 g, although in other embodiments may store such intermediate results in other manners.

After the intermediate data results are available from the worker processes 245 b and 270 b, a worker process 275 b of computing node D 140 d performs one or more interactions 255 h with the online storage service 205 to obtain both of those sets of intermediate data results, and to generate corresponding combined data by performing one or more data manipulation operations previously described with respect to node 275 a of FIG. 2A. In particular, in this example the configurable workflow service has selected computing node D to execute the worker process 275 b, as well as a worker process 280 b that corresponds to node 280 a of FIG. 2A. Thus, after the worker process 275 b produces its results, the process performs one or more interactions 255 j to store those results in the database 210, such as in a manner specified with respect to destination node 230 a of FIG. 2A. In addition, in this example, the worker process 280 b obtains those intermediate data results from worker process 275 b via one or more interactions 255 i, and generates one or more reports in the manner configured with respect to node 280 a of FIG. 1. The worker process 280 b further proceeds to perform one or more interactions 255 k to send those reports to a mailbox 290 of Customer C, such as in a manner specified with respect to destination node 230 b of FIG. 2A.

Thus, in this manner, the logical defined workflow graph 200 of FIG. 2A is implemented via a physical instantiation of that defined workflow using the computing nodes 140 illustrated with respect to FIG. 2B, as well as using intermediate storage to manage the transfer of some or all intermediate data results between workflow worker processes.

It will be appreciated that the examples of FIGS. 2A and 2B are provided for illustrative purposes, and that the invention is not limited by the details discussed with respect to those examples.

FIG. 3 is a block diagram illustrating an example embodiment of a computer system suitable for performing techniques to manage the definition and implementation of workflows for supported client systems. In particular, FIG. 3 illustrates a server computer system 300 suitable for executing an embodiment of a system 340 that provides a configurable workflow service, as well as various client computer systems 350, optional online storage service systems 360, optional online program execution service systems 370, and other computing systems 380. In the illustrated embodiment, the computer system 300 has components that include one or more hardware CPU processors 305, various I/O components 310, storage 320, and memory 330, with the illustrated I/O components including a display 311, a network connection 312, a computer-readable media drive 313, and other I/O devices 315 (e.g., a keyboard, a mouse, speakers, etc.). In other embodiments, the computer system 300 may have more or less components than are illustrated, and the local storage 320 may optionally be provided by one or more non-volatile storage devices that are included within or otherwise locally attached to the computer system 300.

In addition, the illustrated client computer systems 350 have components similar to those of computer system 300, including a CPU 351, I/O components 352 (although particular components are not illustrated), storage 354, and memory 357. The other systems 360, 370, and 380 may also each include similar components to some or all of the components illustrated with respect to computer system 300, but such components are not illustrated in this example for the sake of brevity. The client computer systems 350 each includes a browser program 358 executing in memory 357, such as to enable a user of such a client computer system to interact with a Web-based GUI provided by the configurable workflow service system 340, and also optionally stores information 355 about client-specific workflow components on the local storage 354, although in other embodiments one or both of these components may not be present on some or all client systems. Furthermore, a particular client computer system 350 may have more or less components than are illustrated.

An embodiment of a configurable workflow service system 340 is executing in memory 330 of computer system 300, such as to include software instructions that, when executed by the CPU 305, program or otherwise configure the computer system 300 to perform automated operations to provide some or all of the described techniques. While not illustrated in FIG. 3, the system 340 may include one or more modules, optionally corresponding to modules 120 and/or 130 of FIG. 1. In addition, the server computer system may further optionally execute one or more online storage services 335 and/or one or more online program execution services 337 in memory 330, such as to correspond to situations in which the configurable workflow service system 340 is integrated with or otherwise operates in conjunction with such services 335 and/or 337, although the system 340 may instead operate independently of any such other systems in some embodiments. In other embodiments, any such online storage services and/or online program execution services that are used by the configurable workflow service system 340 may be accessed over the network 390, such as with respect to optional systems 360 and/or 370.

In this example embodiment, the configurable workflow service system 340 includes functionality related to managing workflow-related functionality for supported client systems, and is further optionally configured to interact with client computer systems 350 and/or other systems and devices over the network 390 (e.g., via the Internet and/or the World Wide Web, via a private cellular network, etc.). The other systems 350, 360, 370 and/or 380 may also each be executing various software as part of interactions with the system 340. Various information related to the operation of the configurable workflow service system 340 (and optionally services 335 and/or 337) may be stored in storage 320 or instead remotely, such as information 322 about particular client systems and/or users, information 324 about one or more particular defined workflows for clients, and information 326 about any defined workflow components, such as in a manner similar to that of information 112-116 of FIG. 1 or as described elsewhere herein. Additional details regarding operations of the system 340 in particular embodiments are described in greater detail elsewhere.

It will be appreciated that systems 300, 350, 360, 370 and 380 are merely illustrative and are not intended to limit the scope of embodiments of the present disclosure. For example, system 340 may instead be executed by multiple interacting computing systems or devices, and computing system 300 may be connected to other devices that are not illustrated, including through one or more networks such as the Internet, via the World Wide Web (“Web”), or other electronic communications network (e.g., cellular based network, public switched telephone network). More generally, a computer system or computing system or computing node may comprise any combination of hardware that can interact and perform the described types of functionality, optionally when programmed or otherwise configured by particular corresponding software instructions, including without limitation desktop or other fixed-location computers, laptops and tablets and other mobile computers, database servers, network storage devices and other network devices, PDAs, smart phones and other cell phones, wireless phones, pagers, electronic organizers, Internet appliances, television-based systems (e.g., using set-top boxes and/or personal/digital video recorders), and various other consumer products that include appropriate communication capabilities. In addition, the functionality provided by the illustrated system 340 may in some embodiments be distributed in various modules.

It will also be appreciated that, while various items are illustrated as being stored in memory or on storage while being used, these items or portions of them may be transferred between memory and other storage devices for purposes of memory management and data integrity. Alternatively, in other embodiments some or all of the software modules and/or systems may execute in memory on another device and communicate with the illustrated computer systems via inter-computer communication. Thus, in some embodiments, some or all of the described techniques may be performed by hardware means that include one or more processors and/or memory and/or storage when configured by one or more software programs (e.g., by the system 340) and/or data structures (e.g., defined workflow information 324 and/or defined workflow component information 326), such as by execution of software instructions of the one or more software programs and/or by storage of such software instructions and/or data structures. Furthermore, in some embodiments, some or all of the systems and/or modules may be implemented or provided in other manners, such as by using means (e.g., specialized electronics) that are implemented at least partially or completely in firmware and/or hardware, including, but not limited to, one or more application-specific integrated circuits (ASICs), standard integrated circuits, controllers (e.g., by executing appropriate instructions, and including microcontrollers and/or embedded, controllers), field-programmable gate arrays (FPGAs), complex programmable logic devices (CPLDs), etc. Some or all of the modules, systems and data structures may also be stored (e.g., as software instructions or structured data) on non-transitory computer-readable storage media, such as a hard disk or flash drive or other non-volatile storage device, volatile or non-volatile memory (e.g., RAM), a network storage device, or a portable media article to be read by an appropriate drive (e.g., a DVD disk, a CD disk, an optical disk, etc.) or via an appropriate connection. The systems, modules and data structures may also in some embodiments be transmitted as generated data signals (e.g., as part of a carrier wave or other analog or digital propagated signal) on a variety of computer-readable transmission media, including wireless-based and wired/cable-based media, and may take a variety of forms (e.g., as part of a single or multiplexed analog signal, or as multiple discrete digital packets or frames). Such computer program products may also take other forms in other embodiments. Accordingly, the present invention may be practiced with other computer system configurations.

FIG. 4 is a flow diagram of an example embodiment of a Configurable Workflow Service routine 400. The routine may be provided by, for example, execution of the configurable workflow service 110 of FIG. 1 and/or the configurable workload service system 340 of FIG. 3, such as to manage the definition and implementation of workflows for various remote clients of the configurable workflow service. In this example embodiment, the routine may manage accessing information from and/or providing information to one or more data storage systems or data storage services, whether external to the configurable workflow service routine, or integrated with or otherwise affiliated with the configurable workflow service routine, although the described techniques may be used in other manners in other embodiments.

In the illustrated embodiment, the routine begins at block 405, where an instruction is received related to managing workflow-related functionality. The routine continues to block 410 to determine if the instruction received in block 405 is to define a new workflow on behalf of a client of the configurable workflow service. If so, the routine continues to blocks 415-425 to obtain and store information about a defined workflow for the client. As described in greater detail elsewhere, in some embodiments and situations, the configurable workflow service may provide a user interface via which a user representative of the client interactively specifies information for the new workflow being defined, while in other embodiments the information to use to define a new workflow may instead be received via one or more programmatic interactions from one or more executing programs on behalf of the client.

In the illustrated embodiment, the routine in block 415 optionally provides information to the client about options for defining the new workflow, including system-defined workflow components that are available to be selected and used by the client—such information may be provided, for example, via a GUI of the configurable workflow service by displaying corresponding information and functionality to the user. After block 415, the routine continues to block 420 to receive configuration information to define the workflow for the client. In some embodiments, such configuration information may be received via programmatic interactions with an API of the configurable workflow service, while in other embodiments and situations, the information received in block 420 may be provided via a user representative of the client via a user interface of the configurable workflow service. It will be appreciated that the definition of a workflow via a user interface of the configurable workflow service may involve multiple successive interactions by a user representative of the client, with the configurable workflow service optionally updating and providing additional or alternative information to the user via a user interface based on prior selections that have been made. Thus, the functionality of blocks 415 and 420 may include multiple iterative activities by the configurable workflow service in some embodiments and situations. After block 420, when the definition of the new workflow has been completed, the routine continues to block 425 to store workflow definition information for the client for later use, such as by using a database or other storage location internal to the configurable workflow service. In some embodiments, the client may further provide an instruction to initiate execution of the workflow at this time, such as may be handled with respect to blocks 435-450 of the routine 400.

If it is instead determined in block 410 that the instruction received in block 405 is not to define the new workflow, the routine continues instead to block 435 to determine if the received instruction is to execute an existing workflow, such as an instruction received from a client to initiate current execution (e.g., with respect to a newly defined workflow, as discussed with respect to blocks 415-425), an indication that a scheduled time that was previously specified for such execution has arrived, etc. If so, the routine continues to block 440 to retrieve stored workflow definition information for the client, such as from an internal database or other storage location associated with the configurable workflow service. After block 440, the routine continues to block 445 to select computing nodes to use to execute worker processes for the workflow, and to provision those selected computing nodes for those worker processes. As discussed in greater detail elsewhere, the computing nodes that are selected to be used may have various forms in various embodiments, including computing nodes provided by the configurable workflow service for use by the various clients of the configurable workflow service, computing nodes provided by one or more external (optionally affiliated) program execution services, computing nodes that are provided by or otherwise under the control of the client, etc. In addition, the provisioning of the selected computing nodes may include, for example, loading software to be executed for one or more particular worker processes on each selected computing node, optionally loading data to be used by such worker processes on each selected computing node, etc. After block 445, the routine continues to block 450 to initiate the execution of the worker processes for the workflow being executed on the selected computing nodes. FIG. 5 illustrates additional details of one example embodiment of provisioning and executing a worker process on a selected computing node.

If it is instead determined in block 435 that the instruction received in block 405 is not to execute a defined workflow, the routine continues instead to block 460 to determine if the instruction received is to check preconditions for one or more defined workflows, such as for workflows that are configured to execute when their preconditions are satisfied. If so, the routine continues to block 465 to retrieve information about preconditions for any such defined workflows, and to determine if those retrieved preconditions are currently satisfied. The routine then continues to block 470 to determine if sufficient preconditions have been satisfied for any defined workflows to initiate their implementation, and if so returns to block 440 to initiate execution of each such defined workflow. The instruction to check pre-conditions at a particular time may be initiated in various manners in various embodiments, such as on a periodic basis, in response to indications of events that have occurred (e.g., new arrival or availability of data), etc.

If it is instead determined at block 460 that the instruction received in block 405 is not to currently check workflow preconditions for any defined workflows, the routine continues instead to block 490 to perform one or more other indicated operations as appropriate. The operations performed with respect to block 490 may have various forms in various embodiments and at various times, including to modify or remove defined workflows for clients, stop or otherwise modify current or scheduled executions for defined workflows for clients, check for alarm conditions with respect to any defined workflows and take corresponding action as appropriate, etc.

After blocks 425, 450, or 490, or if it is instead determined in block 470 that no defined workflows have preconditions that are currently satisfied, the routine continues to block 495 to determine whether to continue, such as until an explicit indication to terminate is received. If it is determined to continue, the routine continues to block 405, and otherwise continues to block 499 and ends.

FIG. 5 is a flow diagram of an example embodiment of a Workflow Component Worker Process routine 500. The routine may be provided by, for example, execution of a configured worker process for a defined workflow on a provisioned computing node, such as with respect to the computing nodes 140 and workflow worker processes 142 of FIG. 1 and computing nodes 140 and worker processes 235 b-280 b of FIG. 2B, with respect to computing nodes provided by other external program execution services and corresponding worker processes executed by those computing nodes, and/or with respect to computing nodes provided by or otherwise controlled by the client and corresponding worker processes executed by those computing nodes.

In this example embodiment of the routine, the actions of the routine are illustrated with respect to a single worker process, although it will be appreciated that a particular computing node may execute multiple worker processes in particular embodiments and situations, and that a particular worker process may in some embodiments and situations be executed on multiple computing nodes or other computing systems (e.g., in a distributed manner, such as simultaneously and/or serially on those computing systems). In addition, it will be appreciated that particular workflow component worker processes may perform different operations (e.g., more or less than are illustrated) in accordance with particular configurations for their corresponding workflow components.

The illustrated embodiment of the routine begins at block 505, where configuration information is received for a worker process of a defined workload to be executed, and execution of the worker process is initiated. In some embodiments and situations, the configuration information and execution initiation are received based on one or more interactions with the routine 400 of an embodiment of the configurable workflow service, such as with respect to blocks 445 and 450 of FIG. 4. As discussed in greater detail elsewhere, each worker process may have various associated information, including to be of a defined type, to have defined software code to be executed to implement the worker process, to have one or more defined data sources from which the worker process will receive input, to have one or more defined data destinations to which data results produced by the worker process will be provided, to optionally have other data associated with the worker process (e.g., configuration information related to how the worker processes will perform one or more specified data manipulation operations), to optionally have one or more preconditions and/or post conditions, to optionally have one or more associated alarms, etc. Thus, while not illustrated with respect to the example embodiment of routine 500, in other embodiments, the routine may further receive additional information in block 505 or at other times, including configuration data to be used by the worker process.

After block 505 the routine continues to block 510, where it optionally performs any pre-processing activities for the worker process, such as to prepare the worker process to perform its specified data manipulation operations or other operations. After block 510, the routine continues to block 535, where it obtains source data to be used by the worker process from one or more specified source locations. For example, in some embodiments and situations, preconditions may be used that are based at least in part on determining availability of such source data. After block 525, the routine continues to block 540 to perform one or more specified data manipulation activities for the worker process on the obtained source data. As discussed in greater detail elsewhere, such specified data manipulation activities may have various forms in various embodiments and situations, including to move data from one location to another location, to modify or otherwise transform data in various manners, etc.

After block 540, the routine continues to block 570 to provide the results from the specified data manipulation activities of block 540 to one or more specified destination locations. As discussed in greater detail elsewhere, such activities in providing the results data may include storing some or all of the results data in a specified storage location, sending one or more electronic communications that include some or all of the specified results data, generating a particular report or other format that includes some or all of the results data for presentation, etc.

After block 570, the routine continues to block 595 to determine whether to continue, such as until an explicit indication to terminate is received. If it is determined to continue, the routine returns to block 520, and otherwise continues to block 599 and ends. In the illustrated embodiment, a given worker process may thus perform the activities of blocks 520-570 multiple times if so configured, such as to perform one or more specified data manipulation activities on different groups of source data at different times, including in situations in which the computing node(s) executing the worker process are operated for extended periods of time, such as for multiple implementations of the defined workflow. In other embodiments, the worker process may further at times receive additional configuration information that modifies future performance of the worker process and/or may perform other pre-processing activities at times, and thus in such situations the routine may return from block 595 to blocks 505 and/or 510 if appropriate.

It will be appreciated that in some embodiments the functionality provided by the routines discussed above may be provided in alternative ways, such as being split among more routines or consolidated into fewer routines. Similarly, in some embodiments, illustrated routines may provide more or less functionality than is described, such as when the amount of functionality that is provided is altered. In addition, while various operations may be illustrated as being performed in a particular manner (e.g., in serial or in parallel) and/or in a particular order, in other embodiments the operations may be performed in other orders and in other manners. Similarly, the data structures discussed above may be structured in different manners in other embodiments, such as by having a single data structure split into multiple data structures or by having multiple data structures consolidated into a single data structure, and may store more or less information than is described (e.g., when other illustrated data structures instead lack or include such information respectively, or when the amount or types of information that is stored is altered).

Additional details are included below related to a particular example embodiment of a configurable workflow service, although it will be appreciated that the described techniques are not limited by such details.

In this example embodiment, configurable workflow service (“CWS”) workflows (also referred to as “pipelines” in this example embodiment) are defined via a configuration language that enables description of nodes (also referred to as “objects” in this example embodiment) that form a pipeline. There are 5 general types of objects one can describe in an CWS pipeline in this example embodiment, as follows:

-   -   Data Sources—An input to, or an output from a data manipulation         workflow component (also referred to as an “activity” in this         example embodiment).     -   Activities—An operation to run, such as data processing         transforms and data copies. Activities can be set to alarm on         certain states and to retry multiple times on failure.         Predefined activities include Copy, SQLTransform,         HiveQLTransform, ElasticMapReduceTransform, and         CommandLineTransform.     -   Pre-Conditions and Post-Conditions—An action associated to a         Data Source that evaluates to true when the Data Source is         considered available and/or well formed. Pre conditions that         complete successfully enable a following Activity that consumes         a Data Source as an input to be run. Post conditions that         complete successfully enable an Activity that creates a Data         Source to be considered to be successfully completed.     -   Schedules—An attribute of a Data Source that describes the         periodicity of the data or of an Activity that defines the         periodicity of when it runs, which can be at a granularity of         one or more minutes, hourly, daily, weekly, monthly, etc.     -   Alarms—Describes a message to be published to a notification         service (e.g., Amazon's SNS, or Simple Notification Service),         sent via an electronic communication (e.g., email), etc.         Pipelines and individual Activities may have an Alarm defined         for both failure and for success.

A Pipeline is composed of objects and objects consist of attributes. Attributes have the form tag: value.

Objects have a name: attribute and type: attribute. In addition to name and type, objects may have any number of other attributes depending on the type of the object. In the example below, the object ‘Invoice Logs’ describes a data object stored in an example online storage service SSS (referred to as <online-storage-service-SSS>) and has path: attribute in addition to name: and type:

name: Invoice Logs

type: <online-storage-service-SSS>DataNode

-   -   path: <online-storage-service-SSS>//my_data/xyz.cvs

An attribute may optionally be repeated within an object. In the example below, input: is repeated and the values for each input: attribute are treated as an ordered list:

name: Invoice Processing

type: CommandRunnerTransform

input: Invoice Logs

input: Invoice Dimensions

The value of an attribute may be one of:

an object reference

an expression

a string literal

Here is a brief example showing each type of attribute value:

name: HourPeriod type: Schedule period: “1 hour”←- - This is a string literal

Name: An Object

type: MyTransform dimension: HourPeriod ←- - - - This is an object reference attrib: #{interval.end} ←- - This is an expression

Consider an example of concatenating 5 minute logs into an hourly log. Here is a simple Pipeline that concatenates 5 minute logs into an hourly log in online-storage-service-SSS on a recurring basis. This Pipeline consists of:

an input Data Source—5 minute click logs in <online-storage-service-SSS> a copy Activity an output Data Source (e.g., a data destination node)—1 hour click logs in <online-storage-service-SSS> 2 Schedule objects an Alarm object name: FiveMinPeriod type: Schedule period: “5 minutes” name: HourPeriod type: Schedule period: “1 hour” name: Five Minute Logs type: <online-storage-service-SSS>DataNode dimension: FiveMinPeriod path: “<online-storage-service-SSS>://prod/Clicks/π{interval.end}.csv” name: Concatenate type: CopyTransform dimension: HourPeriod input: Five Minute Logs output: Hourly Logs onFail: CopyFailedAlarm name: CopyFailedAlarm type: “EmailAlarm” to: <client-email-address> subject: “Click 5 min->1 hour Failed!” body:

Error for interval #{node.interval.start} . . . #{node.interval.end}

name: Hourly Logs type: <online-storage-service-SSS>DataNode dimension: HourPeriod path: “<online-storage-service-SSS>://XXX-test/OutData/#{interval.end}.csv”

First, let's describe our 5 minute click logs in additional detail, which are the input to our Pipeline. The following 2 objects define 1) a Schedule(‘FiveMinPeriod’) and 2) a Data Source (‘Five Minute Logs’) that is associated with ‘FiveMinPeriod’:

name: FiveMinPeriod type: Schedule period: “5 minutes” name: Five Minute Logs type: <online-storage-service-SSS>DataNode dimension: FiveMinPeriod path: “<online-storage-service-SSS>://prod/Clicks/#{interval.end}.csv” This has the effect of describing a series of <online-storage-service-SSS> files such as: . . . <online-storage-service-SSS>://prod/Clicks/2011-11-14:10:05:00.csv <on line-storage-service-SSS>://prod/Clicks/2011-11-14:10:10:00.csv <online-storage-service-SSS>://prod/Clicks/2011-11-14:10:15:00.csv <on line-storage-service-SSS>://prod/Clicks/2011-11-14:10:20:00.csv <online-storage-service-SSS>://prod/Clicks/2011-11-14:10:25:00.csv . . . Each such online-storage-service-SSS file can be thought of as an instance of ‘Five Minute Logs’. Each one is distinct from the others based on the time period they represent, and the data that they include.

Further consider the object information shown below:

name: Five Minute Logs type: <online-storage-service-SSS>DataNode dimension: FiveMinPeriod path: “<online-storage-service-SSS>://prod/Clicks/#{interval.end}.csv”

The type: attribute identifies this as an <online-storage-service-SSS>DataNode source object. The name: can be anything, but in this example embodiment may be unique for this Pipeline definition. Data Source objects such as <online-storage-service-SSS>DataNodes may also have a dimension attribute in this example embodiment, which describes different ways an object can be materialized into occurrences. One common example of dimension is time period, which can be expressed as minutes, hours, days, weeks, or months. Another example dimension is one based on geographic regions, such as to correspond to different locations of data source systems.

In addition, time periods may be specified by schedule objects in this example embodiment. In particular, we define a schedule object that specifies a 5 minute period as follows:

name: FiveMinPeriod type: Schedule period: “5 minutes” Notice ‘Five Minute Logs’s dimension: attribute refers to the schedule object ‘FiveMinPeriod’. Now let's looks at the path: attribute: path: “<online-storage-service-SSS>://prod/Clicks/#{interval.end}.csv” The sequence ‘#{ }’ describes an expression. In this case the expression to be evaluated is interval.end. Because ‘Five Minute Logs’ has a schedule associated with it, it contains an attribute called ‘interval’, which itself has a ‘start’ and ‘end’ value. In this way, interval.start . . . interval.end describes a specific time interval of a schedule: . . . interval.start 2011-11-14:10:00:00 interval.end 2011-11-14:10:05:00 interval.start 2011-11-14:10:05:00 interval.end 2011-11-14:10:10:00 interval.start 2011-11-14:10:15:00 interval.end 2011-11-14:10:20:00 . . . The path: attribute is evaluated as an <online-storage-service-SSS> file name using the end of each 5 minute interval per the schedule object in this case.

Next, let's describe an activity that reads an hour's worth of 5 minute clicks and concatenates them into an hourly output file. These 3 objects define 1) a Schedule (‘HourPeriod’), 2) a CopyTransform (‘Concatenate’) that is associated with ‘HourPeriod’, and 3) an Alarm (‘CopyFailedAlarm’) that will be invoked the event of failure:

name: HourPeriod type: Schedule period: “1 hour” name: Concatenate type: CopyTransform dimension: HourPeriod input: Five Minute Logs output: Hourly Logs onFail: CopyFailedAlarm name: CopyFailedAlarm type: “EmailAlarm” to: <client-email-address> subject: “Click 5 min ->1 hour Failed!” body:

Error for interval #{node.interval.start} . . . #{node.interval.end}

CWS schedules and runs ‘Concatenate’ when an hour's worth of input: (‘Five Minute Logs’) is available. When all 20 5-minute files for a given hour are ready, each will be copied into output ‘Hourly Logs’. If the ‘Concatenate’ process encounters a failure condition, the Alarm object ‘CopyFailedAlarm’ will run and send an email.

In particular, ‘Concatenate’ is an object of type ‘CopyTransform’, which is a built-in Activity provided by CWS in this example embodiment. The CopyTransform takes an input Data Source and an output Data Source. Activities (CopyTransform is a type of Activity) may have a Schedule dimension associated with them, just like a Data Source. In this case, ‘Concatenate’ is associated with the Schedule object ‘Hour Period’, which describes an hourly time interval. This can be thought of as the following: “‘Concatenate’ processes 1 hour's worth of data”.

The Schedule of the input: in this case (‘Five Minute Logs’) describes a 5 minute interval, while the schedule of ‘Concatenate’ is hourly. CWS infers that 20 5-minute input files map to the hourly interval of processing ‘Concatenate’ is configured for. An Alarm object such as ‘CopyFailedAlarm’ can be associated with any number of Activities. The body: attribute in this case contains the following expressions: Error for interval #{node.interval.start} . . . #{node.interval.end}. Alarms have a node: attribute that at runtime evaluates to the object the Alarm is reporting on. In this case, the ‘node’ would refer to the object ‘Concatenate’ if the alarm was fired due to a failure with ‘Concatenate’.

Finally, here is our output Data Source:

name: Hourly Logs type: <online-storage-service-SSS>DataNode dimension: HourPeriod path: “<online-storage-service-SSS>://prod/concat-clicks/#{interval.end}.csv”

This has the effect of describing a series of <online-storage-service-SSS> files such as:

. . . <online-storage-service-SSS>//prod/concat-clicks/2011-11-14:00:0:00.csv <online-storage-service-SSS>://prod/concat-clicks/2011-11-14:01:0:00.csv <online-storage-service-SSS>://prod/concat-clicks/2011-11-14:02:0:00.csv . . . Each <online-storage-service-SSS> file may be thought of as an instance of ‘Hourly Logs’. Each one is distinct from the others based on the time period they represent, and the data that they include.

Further consider the following:

name: Concatenate type: CopyTransform dimension: HourPeriod input: Five Minute Logs output: Hourly Logs name: Hourly Logs type: <online-storage-service-SSS>DataNode dimension: HourPeriod path: “<online-storage-service-SSS>://prod/concat-clicks/#{interval.end}.csv”

Like the ‘Five Minute Logs’ Data Source described above, ‘Hourly Logs’ is associated with a Schedule, which in this case is an hourly Schedule. The path: attribute is evaluated as an <online-storage-service-SSS> file name using the end of each hourly interval per the schedule object in this case.

The ‘Concatenate’ Activity specifies ‘Hourly Logs’ as the output Data Source. When CWS schedules and runs ‘Concatenate’, it also will give rise to an <online-storage-service-SSS> file corresponding to the ending time range of the hourly schedule period for the current run.

The value of an attribute can take the following forms:

an object reference an expression a string literal

With respect to object references, an attribute can refer to another Pipeline object by name. This useful in forming certain types of expressions:

name: object1 type: sample name: object2 type: sample attrib1: object1<- - - - - - Reference to object1

With respect to expressions, an expression occurs within this construct: #{“expression” }. Expressions can be

a built in function:

attrib: #{day(currentTime( ))}

a string value:

attrib: #{“this is a string value”}

concatenation of string terms:

attrib: #{“prefix-”+ functionReturningString( )}

an integer or floating point value:

attrib: #{func(3.14, 5)}

numeric expressions:

attrib: #{func(3.14+5)}

a simple reference to another attribute

name: object1

type: sample

attrib1: #{today( )}

attrib2: #{attrib1}<- - - - - - - attrib2 will have the value of attrib1

a qualified reference to another attribute

name: object1

type: sample

attrib1: #{today( )}

attrib2: attrib1

name: object2

type: sample

attrib3: object1<- - - - - - - An object reference, does not appear inside the ‘#{ }’ construct

attrib4: #{attrib3.attrib2}<- - - - - - - This is a qualified attribute reference (value is object1.attrib2)

With respect to string literals, an attribute can have a string literal value, such as “this is a string literal”. Also, a string literal can contain an expression, which is evaluated as a string:

attrib1: “This contains an #{attrib2}”

attrib2: “expression”

Notice that attrib1 above has an expression embedded via the expression construct: ‘#{ }’

String literals can also be multi-line. In this case, each line indented 2 spaces:

attrib3:

-   -   This is line one     -   This is the second line     -   And this is the last line

As noted above, these details of these example embodiments are provided for the purpose of illustration, and are not intended to limit the scope of the described techniques with respect to other embodiments.

From the foregoing it will be appreciated that, although specific embodiments have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims and the elements recited therein. In addition, while certain aspects of the invention are presented below in certain claim forms, the inventors contemplate the various aspects of the invention in any available claim form. For example, while only some aspects of the invention may currently be recited as being embodied in a computer-readable medium, other aspects may likewise be so embodied. 

1-3. (canceled)
 4. A computer-implemented method comprising: receiving, by one or more configured computing systems of a configurable workflow service, configuration information for a defined workflow of a client of the configurable workflow service, the configuration information specifying multiple workflow components of the defined workflow and interconnections between at least some of the multiple workflow components; provisioning, by the one or more configured computing systems, multiple computing nodes to each implement at least one of the multiple workflow components, at least one of the multiple computing nodes being provided by the configurable workflow service for use by clients of the configurable workflow service; and implementing the defined workflow for the client by initiating performance of defined activities on the multiple computing nodes that correspond to the implemented workflow components, the defined activities including: one or more first activities involving obtaining input data from one or more data sources external to the configurable workflow service; one or more second activities involving producing intermediate results data by performing data manipulation operations that are based at least in part on the obtained input data; and one or more third activities involving producing output data based at least in part on the intermediate results data of the second activities.
 5. The method of claim 4 wherein the implementing of the defined workflow for the client further includes at least one of storing the produced output data in one or more storage locations specified by the client, and generating one or more reports that are based at least in part of the produced output data and that are provided to the client.
 6. The method of claim 4 further comprising: receiving indications of one or more criteria for initiating implementation of the defined workflow; and before the implementing of the defined workflow, determining, by the one or more configured computing systems, that the one or more criteria are satisfied.
 7. The method of claim 6 wherein the one or more criteria correspond to periodic implementation of the defined workflow at multiple times based on changing input data that is available at those multiple times, and wherein the method further comprises performing the implementing of the defined workflow at each of those multiple times.
 8. The method of claim 6 wherein at least one of one or more criteria is defined as a pre-condition associated with at least one of the multiple workflow components.
 9. The method of claim 6 further comprising receiving information about a post-condition criterion associated with one of the multiple workflow components, and wherein the implementing of the defined workflow further includes determining that the post-condition criterion is satisfied after the performing of one or more of the defined activities that correspond to the one workflow component.
 10. The method of claim 6 wherein the determining that the one or more criteria are satisfied occurs at a first time, and wherein the method further comprises: determining, by the one or more configured computing systems, that the one or more criteria are not satisfied at a second time; and in response, generating an alarm notification for the client to indicate that the one or more criteria are not satisfied.
 11. The method of claim 4 further comprising: providing a graphical user interface, wherein the client specifies by the configuration information via the graphical user interface by editing a graph that logically represents the defined workflow, each of the multiple workflow components being indicated within the graph by at least one of multiple nodes of the graph; and wherein the implementing of the defined workflow includes physically instantiating a copy of the graph.
 12. The method of claim 4 further comprising implementing the defined workflow for the client at multiple distinct times, and wherein one or more of the multiple computing nodes are maintained between the multiple distinct times to enable the provisioning of the one or more computing nodes to occur only once.
 13. (canceled)
 14. The method of claim 4 wherein the provisioning of the multiple computing nodes includes, for each of the multiple computing nodes, loading at least one of a software program and configuration data on the computing node.
 15. The method of claim 4 wherein one or more of the multiple computing nodes are provided by an online execution service external to the configurable workflow service, and wherein the provisioning of the one or more computing nodes includes performing, by the one or more configured computing systems, one or more interactions with the online execution service corresponding to the one or more computing nodes.
 16. The method of claim 15 wherein the provided one or more computing nodes are associated by the online execution service with an account of the client with the online execution service, and wherein the one or more interactions with the online execution service include providing information on behalf of the client to the online execution service regarding the account of the client.
 17. (canceled)
 18. The method of claim 4 wherein the multiple workflow components include one or more source components and one or more data manipulation components and one or more destination components, each of the one or more source components having an associated data source and associated instructions for accessing at least some of the input data from the associated data source, each of the one or more data manipulation components having associated instructions for performing at least one of the data manipulation operations, and each of the one or more destination components having associated instructions of handling at least some of the output data that is produced.
 19. The method of claim 18 wherein the multiple workflow components further include multiple of the source components, and wherein at least one of the source components is supplied by the client to the configurable workflow service to enable access to a data source that is specific to the client.
 20. The method of claim 18 wherein the multiple workflow components further include multiple of the data manipulation components, and wherein at least one of the data manipulation components has an associated data manipulation operation that is supplied by the client to the configurable workflow service to enable performance of a defined activity that is specific to the client.
 21. (canceled)
 22. The method of claim 4 further comprising, for each of multiple additional clients of the configurable workflow service: receiving configuration information for an additional defined workflow of the additional client; storing the configuration information for an additional defined workflow of the additional client on one or more storage mechanisms of the configurable workflow service; and implementing the additional defined workflow on behalf of the additional client on one or more computing nodes at one or more times.
 23. A non-transitory computer-readable medium having stored contents that configure a computing system of a configurable workflow service to: provision, by the configured computing system, multiple computing nodes based on configuration information supplied by a client for a defined workflow, the provisioning including configuring the multiple computing nodes to implement multiple workflow components for the defined workflow, the defined workflow including interconnections between at least some of the multiple workflow components; and implement the defined workflow for the client by initiating performance of defined activities on the multiple computing nodes that correspond to the implemented workflow components, the performance of the defined activities including obtaining input data from one or more data sources, performing data manipulation operations that are based at least in part on the obtained input data, and producing output data based at least in part on the performed data manipulation operations.
 24. The non-transitory computer-readable medium of claim 23 wherein the configurable workflow service provides a plurality of computing nodes for use in implementing workflows for multiple clients of the configurable workflow service, wherein at least some of the multiple computing nodes are a subset of the plurality of computing nodes, and wherein the stored contents are software instructions that, when executed, program the configured computing system.
 25. The non-transitory computer-readable medium of claim 23 wherein the computing system is further configured to, before the provisioning of the multiple computing nodes: provide one or more interfaces for use by clients of the configurable network service in specifying information; and receive configuration information from the client for the defined workflow via at least one of the provided interfaces, and wherein the defined activities are performed in accordance with the received configuration information.
 26. The non-transitory computer-readable medium of claim 23 wherein at least some of the multiple computing nodes are provided by one or more program execution services external to the configurable workflow service, and wherein the computing system is further configured to interact with the one or more program execution services on behalf of the client as part of the provisioning of the multiple computing nodes. 27-30. (canceled) 